


The Truth About A Rat

by FantasticNumberNine



Series: John Watson and the Prisoner of Azkaban [10]
Category: Harry Potter - J. K. Rowling, Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Crossover, Gen, M/M, More Johncroft, Potterlock, Stuff goes down, Surprise! - Freeform, alas, apparently I have a lot of feelings about this scene in canon?, buckbeak loses his trial, exam time!, he's also not really a rat, john speak for kissing, scabbers isn't dead, still no clue how Myc gets to all his classes, they talk about "the thing"
Language: English
Status: Completed
Published: 2015-07-17
Updated: 2015-07-17
Packaged: 2018-04-09 17:31:13
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,333
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4358048
Author URL: https://archiveofourown.org/users/FantasticNumberNine/pseuds/FantasticNumberNine
Summary: <blockquote class="userstuff">
              <p>John and Mycroft talk about "that thing that happened," and then it's time for exams and Buckbeak's appeal--which goes horribly, but John, Greg, and Mycroft get understandably distracted by Sirius Black.</p>
            </blockquote>





	The Truth About A Rat

**Author's Note:**

> *disclaimer*
> 
> This scene fought me for every inch. Rude. And, it seems, that all my love for Sirius doesn't mean I've got nothing to say on how he handled himself in the books. I didn't expect that to come out here...

John and Mycroft sat in the stands the Sunday afternoon after the Quidditch final, watching Greg loop around the pitch on John's Firebolt, whooping joyfully.

Mycroft had been talking John through an Arithmancy problem, but they'd finished that and now they sat quietly. John was fidgeting. 

"Are you going to say what's on your mind, or do I have to guess?" 

Mycroft wasn't looking at him, which was a relief. John shrugged anyways, "You'd probably guess right and spare me the effort of saying it."

Mycroft hummed in agreement, but said nothing. 

John groaned, "Fine. Yesterday. You, the, the thing--" John gestured incomprehensibly.

Mycroft stared at him in amusement, copying John's hand movement, "Is that some heretofore unknown form of sign language?"

"You're making this purposefully harder on me," John whined, rubbing at his face with both hands.

"You are being far more entertaining than I could have hoped for," Mycroft was smiling, it was an admittedly nice smile.

"You kissed me!" John half shouted. He bit his lip and stared at his hands, "Why?"

"We could pretend it never happened, if you prefer," said Mycroft softly.

John looked up at him, incredulous. "The whole school saw, I really doubt we can go on like it never happened."

"No, I suppose not. So the question remains, what do you want to do about it?" 

John shrugged again, "Dunno. Actually, wait. You kissed _me_!"

"Yes," Mycroft said slowly, "I did kiss _you_."

"I thought you wanted to kiss Greg!" John looked very confused, and very slightly guilty.

Mycroft sighed.

"After everything that has happened this year, I've rather lost track of wanting Gregory in that sort of capacity," Mycroft paused. "Temporarily, at the very least. Perhaps the interest will return in the future. We are, after all, only fourteen."

"Almost," John corrected.

"I meant Gregory and I, but yes. I should probably have included you. Fourteen- and thirteen-year-olds have no business thinking long term," Mycroft finished sagely.

"What? So I'm not the Viola to your Orsino?" John slapped his hand dramatically against his heart, grinning when Mycroft laughed loudly.

"Why, John! You know your Shakespeare!" Mycroft's Admittedly Nice Smile was back.

"You called Moriarty a 'paper-faced villain,'" John remembered fondly. "Do wizards know Shakespeare?"

"He was muggle-born, so I highly doubt any pureblood of Jim Moriarty's standing would have any desire to know Shakespeare--though I imagine if they do, they very willfully ignore his status of birth." Mycroft made a soft face of disgust.

"No! Shakespeare was a wizard? You're having me on!" John pushed at Mycroft's shoulder playfully.

Mycroft grabbed John's hand, his smile knowing. "Have you read _The Tempest_ or _Midsummer Night Dream_? Even The Scottish Play has obvious overtures!" 

There faces were very close now, and Mycroft's eyes were lit up.

"What, so every writer ever who's written about magic is a wizard? Or a witch?" John asked, happily skeptic.

"Obviously," Mycroft leaned in, quick as a Snitch, and stole a quick kiss, before standing and heading down to the pitch, where Greg was finally touching down. "My turn, I should think."

"Oh." John blinked, a bit stupidly. Then, "Hey! You don't get to distract me like that and run away! I'll believe Tolkien and Lewis, but what about Roald Dahl?"

Gryffindor's euphoria at winning the Quidditch Cup lasted until the last few weeks before the end of the year exams arrived and took the entire castle by surprise.

Greg had finally given up on asking Mycroft how he was getting to all his classes, until he saw Mycroft's exam schedule.

MONDAY  
9 o'clock Ancient Runes  
9 o'clock Transfiguration  
Lunch  
1 o'clock Charms  
1 o'clock Muggle Studies

"Er, Mycroft?" Greg said cautiously, because he was liable to explode when interrupted these days. "Are, are you sure you've copied these times down right?"

"Yes, of course I have," he snapped.

"Any point asking how you'll sit two exams at once?" John asked, sitting squished in the large armchair with Mycroft.

" _No_ ," Mycroft said shortly. "Has either of you seen my copy of _Numerology and Grammatica_?"

"Oh yeah, I borrowed it for a bit of bedtime reading," Greg murmured, too quiet for Mycroft to hear over his shuffling notes. John kicked him in the shin.

"Here, borrow mine," John pulled his copy up from the floor and handed it over. Mycroft accepted it with a noise that might have been a thank you, but John was distracted by Hedwig's appearance at the open window.

He got up as she's fluttered toward him, a note clutched tight in her beak.

"It's from Hagrid!" John ripped open the note as Mycroft appeared very close beside him, stroking Hedwig softly. "Buckbeak's appeal is set for the sixth."

"That's the day we finish our exams," said Mycroft, as Hedwig nipped his fingers gently before flying off.

"And they're coming up here to do it," John continued, still reading. "Someone from the Ministry, and--and an executioner." 

Greg came up on John's other side abruptly, "What? That sounds like they've already decided!"

"Yeah, it does." 

"They can't! I spent ages reading up on it, that's not even legal!" Greg shouted, and kicked at the chair John and Mycroft had vacated.

On the last day of exams, after their exam with Lupin's Defense Against the Dark Arts test (Greg was struggling not to giggle at Mycroft's Boggart), they were stopped abruptly from going out to the grounds by the sight of Cornelius Fudge just outside the open doors of the entry hall; a large man with a large, shining, axe joined him.

John and Mycroft had to drag Greg away before he could say anything foolish, "You're dad works at the Ministry, Greg, maybe rethink shouting at his boss..."

The boys had one final examination that afternoon: Divination for John and Greg, and Muggle Studies for Mycroft. Up on the seventh floor, their classmates were sitting along the spiral staircase to Trelawney's tower.

"She's seeing us all separately," Molly told them, not looking up from her copy of _Unfogging the Future_.

When Greg's turn came, John waited, alone, for twenty minutes before he reappeared, sliding down the ladder with abandon.

"How'd it go?" John asked, standing.

Greg shrugged, "Couldn't see a damn thing, so I made some stuff up. Rubbish, you know."

Then it was John's turn.

The stuffy room was worse than usual, the heat was overbearing and the perfumed smoke was thick enough that breathing was a challenge. John saw nothing in the swirling white depths of the crystal ball, but he was determined to leave as soon as possible--his Arithmancy exam had been easier. He decided to take a page from Greg's book.

Professor Trelawney was evidently disappointed by the happy end to John's made up prophesy, but as he turned to leave, the strangest thing happened.

" _The Dark Lord lies alone and friendless, abandoned by his followers. His servant has been chained these twelve years. Tonight, before midnight, the servant will break free and set out to rejoin his master. The Dark Lord will rise again with his servant's aid, greater and more terrible than ever before. Tonight... before midnight... the servant... will set out... to rejoin... his master..._ "

John had no idea what had just happened--had that been a true prophecy? Or just a dramatic end to his exam? Mycroft would know.

Mycroft was sitting in their usual corner of the common room with Greg, one look at their faces was enough for John to forget what had happened with Trelawney.

"Buckbeak lost," Greg said, his voice shaky, "The execution's at sunset."

John gaped at them. "We've got to go, Hagrid can't just sit alone waiting for the executioner!"

"Right," Greg muttered despondently. "We'll just go down to Hagrid's for sunset and hope no one stops us, you especially."

"Tragedy is no reason to lose your head, Gregory," said Mycroft, standing abruptly. "We'll use John's invisibility cloak."

They snuck out after dinner, not returning to Gryffindor tower with their classmates.

Hagrid, despite being upset that they'd come, let them into his cabin readily enough. He tried serving them tea, but his hands trembled tremendously, and a milk jug was shattered; Mycroft took over from there.

John and Greg were attempting to console Hagrid when Mycroft let out a strangled yelp.

"Gregory! It's--it doesn't make sense--it's _Scabbers_!"

Greg's mouth dropped open ridiculously, "What?"

Mycroft brought the jug over to the table and turned it upside down, and out slid a dreadful looking Scabbers, who immediately attempted a pitiful escape only to be caught and cradled close by a very stunned Greg.

There was no time to question Scabbers surprise reappearance, the executioner was on his way, with Cornelius Fudge and Professor Dumbledore at his side.

John, Greg, and Mycroft scrambled back under the invisibility cloak and out the back door. 

"Go quick," Hagrid told them. "An' don't listen..."

They started up towards the castle as quick as they could with three under the cloak, but didn't get far before Greg suddenly stopped.

"Gregory, what _is wrong with you_?" Mycroft hissed.

"It's Scabbers, he keeps trying to get away!" Greg hissed back. "Ah! He bit me!"

"Quiet!"

"I should have left the damn thing with the milk--"

Greg wrenched the cloak off of himself, tearing after Scabbers.

"Greg!" John was going to kill him.

Mycroft grimaced, and turned to John, both still under the cloak, "I will help you hide his body."

"Thanks," John growled. He took off the cloak, stuffed it back in his robes, and ran after Greg, Mycroft close behind him.

Greg had jumped on top of Scabbers and was whispering to him in a frantic attempt to calm him down when John and Mycroft caught up to him--and it might have worked, if Crookshanks hadn't chosen that moment to show up, leaping at Greg ferociously.

"No--Crookshanks!" Mycroft ripped him off Greg, but Crookshanks fought back, scratching long tears into Mycroft's sleeves. "Agh! Stop--making--this--worse!"

John had no idea how to help, and they were making a lot of noise, surely someone had heard them by now--he spun around, looking for the castle doors, how had they gotten so far from the path? 

Then a large black shape--the dog! The same one from Magnolia Crescent, he'd bet his Firebolt on it--hurtled towards him, the force of the impact sent John sprawling backwards and the dog rolled past him. John couldn't breathe, he felt like his ribs had broken, and it took too much work to roll onto his knees.

The dog growled at John before leaping at Greg, who had finally gotten to his feet, and tackling him back to the ground and dragging him away by his arm as Greg yelled.

"Greg!" John jumped forward, only to be thrown back as something hit him hard in the face, landing hard on his back once more. He lay there for a moment, dazed and out of breath until he heard a loud and gruesome SNAP!

Then Mycroft was there, pulling him to his feet and shooting a stream of red sparks into the air before they followed Greg and the dog under the Whomping Willow.

They found Greg in a dusty bedroom, white-faced, and sitting on the dusty floor with his back against a dusty four-poster--one hand tightly gripping Scabbers in his shirt, and the other clutching his awkwardly bent leg.

John and Mycroft dashed forward, dropping to their knees on either side of Greg.

"Gregory!"

"Where's the dog?"

"S'not a dog..." Greg grit out through clenched teeth. "Animagus!"

"What d'you mean? Who's--?" 

By the time John had put it together, Mycroft had already shoved him forcefully out of the way and behind a fallen dresser.

" _Expelliarmus_!"

Mycroft had sacrificed his wand so John could keep his--John was both grateful and skeptical of his chances, Mycroft was much cleverer than him.

"Come on out, John, your father would never have hidden when he thought his friends were in danger--though I am grateful you didn't run for a teacher, it'll make everything easier..."

A hatred stronger than John had ever known clouded his soul, how _dare_ Black speak to him of his father? 

"Don't listen to him, John," Mycroft said, his voice deceptively calm.

But it was Greg's voice that kept John from leaping out from behind the toppled dresser.

"You don't get to talk to John, you wanker! And if you're aiming to kill him, you'll have to get through us first!" Greg shouted fiercely, he had pulled himself to his feet, and from what John could see, he was was holding on desperately to the four-poster.

"Sit down, kid," Black said quietly. "You'll damage that leg even more."

"Did you hear me? You'll have to kill all three of us!"

"There'll only be one murder here tonight."

John could hear the grin in Black's voice and he snapped. He was on his feet in the next moment, his wand pointed at Black's heart.

"Yeah? Didn't care last time, did you? When you blew up a whole street just to get at Pettigrew! Gone soft in Azkaban?"

"John, don't--" 

"HE KILLED MY MUM AND DAD!" 

John forgot all about magic, forgot that he was a tiny thirteen year old boy, forgot that Black was a full grown man. He dropped his wand and jumped, fists flying, at Sirius Black, wanting nothing but to hurt the man who had betrayed his parents.

Mycroft would maintain later that the only reason John's attack was remotely successful was because no one could have considered that level of stupidity to be possible.

The brawl was brief, ending because Mycroft had the presence of mind to use John's abandoned wand to steal back his and Greg's wands, pushing John and Black apart in the process.

"John, stop! Think!" Mycroft had thrust Greg's and John's wands at Greg before pulling John to his feet and flush against his chest, his own wand leveled around John's body at Black, who still lay shocked and panting on the ground. "Suppose you succeeded in killing him, then what happens?"

John struggled against Mycroft's surprisingly strong grip, "Then I get the satisfaction of avenging my parents!"

"Vengeance, John? Is that what you stand for?" The disappointment in Mycroft's quiet voice was heavy and unexpected.

John slumped, leaning back against Mycroft, "He killed my parents..." 

"And he will answer for it--"

Footsteps echoed through the shack, and everyone's heads snapped toward the door as it burst open, admitting Professor Lupin who took in the scene quickly before placing himself between Black and his students.

"Sirius," Lupin murmured. "Unfortunately, I can't say I'm happy to see you again."

Black propped himself up against the wall, a look that almost passed for smugly arrogant on his gaunt face.

"Bet I could change your mind quickly enough," Black said, his voice still gruff from disuse.

"I'm not your faithful tag-along anymore, Sirius," Lupin had gone suddenly stiff at Black's words, and John felt Mycroft's silent huff of breath against his ear--he had deduced something John had missed.

"You were much more than that, old friend," Black smiled--or he tried to, what could have once been charming was now a bit frightening on his hollowed out face.

Greg spoke up then, "Er, more urgent, probably, the escaped murdering maniac wants to kill us? Also, my leg is broken."

Lupin steadied his wand, "Quite right, Greg."

"Wait!" Black threw his hands out in front of himself desperately, "The rat! Remus, please, look at the boy's rat! You'll regret it if you don't!"

"Oi! There's nothing wrong with Scabbers!" 

In fact, Scabbers seemed quite healthy all of a sudden as he renewed his attempts at escaping Greg's hold, his little paws dark with Greg's blood.

"The rat? Sirius, you're not saying--"

Mycroft's arm tensed around John's waist, "How long did you say Scabbers had been in your family, Gregory?"

"Twelve--years--dammit! Scabbers!" Greg shouted; all his wriggling to keep a hold of Scabbers had caused him to twist his bad leg.

" _Ferula_ ," said Lupin, finally turning his wand from Sirius Black and aiming it at Greg's leg: bandages spun up the broken leg, strapping it tightly to a splint. "I'm afraid that's the best I can do for you, Greg, until we get you up to the hospital wing."

Greg nodded wordlessly, his face was grey and his eyes were squeezed shut. Lupin hesitated, looking hard at the rat in Greg's mauled hands, but Mycroft saw all he needed; letting go of John, he turned swiftly, and the combined efforts of Scabbers trying to escape and Mycroft pulling him away was too much for Greg.

" _Petrificus Totalus_!"

"Mycroft--"

"We all thought Sirius Black was the man who betrayed your parents, the evidence that day would have been overwhelmingly damning, but the Ministry was missing half the facts and--typical--made the evidence they _did_ have fit what they wanted to see," Mycroft paused, he'd been looking at John as he spoke, but he turned for a moment to face Black, who was still sitting against the wall. "Perhaps if you'd thought to register your animagus forms, your trial would have gone differently."

Black snorted a laugh, "There wasn't a trial."

Mycroft's eyes narrowed.

"Are you saying Greg's rat is possibly an animagus?" John asked, confused.

"No, John," said Lupin. "Greg's rat _is_ an animagus." 

"So he's saying that Sirius Black broke out of Azkaban, ran to Hogwarts, attacked a _painting_ , and dragged Greg into what I'm fairly certain is the Shrieking Shack, because he's after some unregistered, rat animagus?"

"Not some rat, John. Peter Pettigrew." Black had stood, but he stayed near the wall.

John stared at Black, incredulous. "I may be wrong, but, didn't you kill Pettigrew?"

"I tried to," Black growled, glaring at Scabbers, frozen still in Mycroft's hand. "But Peter got the better of me that night--shouted for the whole street to hear that I'd betrayed Lily and James before he cut off a finger and blew up the street--but the little bastard isn't getting away this time!"

Black leapt towards Mycroft, his hands outstretched, but Lupin caught him, throwing him back towards the wall with unexpected strength.

"No! Sirius, you've got a lot more explaining to do!" Lupin stood between Black and his students, "You owe John that much."

"What more is there to say? The little rat betrayed James, now I'm going to make him pay!" 

He jumped forward again, and Lupin threw him back once more with a growl.

"John has only ever known your name as that of the Death Eater who got all of his friends killed! John is an _orphan_ , Sirius, because of you and your secrets!"

"We all had secrets, Remus! Or did you forget yours?" Black snarled.

"James and Lily didn't die for mine!" Lupin snapped.

A heavy silence fell over the Shack, disturbed only by the occasional creaking and the wind outside.

"James and Lily were hiding under a Fidelius Charm, with John. They knew they'd been targeted by Voldemort, and it was the only way they'd be safe," Black said quietly. "They wanted to make me Secret Keeper--I'd be the only person able to reveal their location to anyone."

John frowned, looking to Mycroft, who nodded almost imperceptibly, looking like the final puzzle piece had fallen into place.

"You were the obvious choice," Mycroft continued for Black, "You thought you would be targeted and tortured into betraying your friends, but they couldn't extract the Watson's whereabouts if you _weren't_ the Secret Keeper--"

Lupin cut in, "You switched. You switched and you didn't tell anyone."

Black nodded, guilt and shame evident on his gaunt face. 

"We knew there was a spy..." Black trailed off.

"And you thought it was me," Lupin sighed.

"Yes, quite the tragic tale you've woven," sneered the cold voice of Professor Snape as he stepped into the room, his wand pointed at Lupin.

**Author's Note:**

> It's amusing how many more hits a story will get when you slap a pairing on it...
> 
> GoF will be interesting.


End file.
